Late infantile ceroid lipofuscinosis (LINCL) is a rare, rapidly progressing lysosomal storage disease. The rareness of the patients as well as the possibility of non-uniform progression depending on genotype mean that limited data is available that delineates the natural history of disease progression. The primary focus of this study is to use clinical rating scales and magnetic resonance imaging methods to define the natural history of LINCL and to provide objective and sensitive surrogates for neurological status and for the assessment of the impact of experimental treatments in children with LINCL. To achieve this goal we have 3 aims: (1) Recruit children with LINCL and perform serial neurological assessments and MRI studies;(2) Using this data, expand the spectrum of existing quantitative MRI parameters and derive normal ranges and correlate with neurological status and specific mutations;and (3) Extract additional parameters from MRI data including volumes of brain substructures, local metabolite levels by magnetic resonance spectroscopy and local diffusion weighted imaging. Together, these parameters will be applicable to future clinical studies of novel therapies for LINCL, and should be transferable to other neurological lysosomal storage diseases.